Rapid and accurate diagnosis of acute myocardial infarction (AMI) is extremely important for saving lives. One of the most accurate methods of diagnosis is quantifying various cardiac markers in blood plasma. The accurate information on the levels of these cardiac markers not only provides accurate diagnosis but also is highly beneficial for prescribing an effective regimen for the treatment of the patient. Currently, there are several biosensors that can detect these cardiac markers. However, they are usually for individual cardiac markers and/or do not provide the actual levels of these markers. Here, we propose developing a highly portable, multiple cardiac marker system for quantifying multiple cardiac markers in real-time (less than 3 min), by utilizing the following novel concepts: (a) the growth of a nanowire (NW) in a well-defined path, requiring minimal microfabrication;(b) label-free sensing by polymer conductometric NWs for much simpler and cost-effective assay;and (c) incorporating highly sensitive field effect transistor (FET) detection in the sensing device. Utilizing the novel concepts, a model sensing system is proposed to develop four represented cardiac markers (myoglobin, B-type natriuretic peptide, cardiac troponin I, and creatin kinase-MB). This R21 application describes a plan to: (a) develop an effective method for monoclonal antibody immobilization on/into single polymer NWs (SPNWs);(b) optimize sensors by varying system and operational parameters, e.g., diameter and length of the sensing NWs, the assay time, etc.;and (c) develop a highly sensitive FET for each sensor, to enhance the sensitivity. For the R01 study, utilizing microelectromechanical system (MEMS) technology, the four sensors will be put into one sensing chip with proper microfluidics and all components of the system will be placed in one package (all-in-one system). The system will also be fully automated with digital display of the final results, for user-friendly operation. The resulting highly sensitive, label-free polymer NW sensing system will provide the levels of multiple cardiac markers in blood plasma in real-time, providing clinicians with the crucial information for early and accurate diagnosis of AMI and/or for the accurate design of an effective regimen for individual patients. The rapid, accurate, and cost-effective diagnosis of AMI and proper AMI patient treatment will reduce the enormous expense for health care. The entire sensing system is highly portable and, therefore, can be placed at a patient's bedside and/or inside emergency medical service vehicles. The same concept used for this device can be used for other disease diagnosis (e.g., cancer) and also for environmental or safety-related monitoring. Cardiovascular disease is the leading cause of death in the United States and in the Western world. The rapid, accurate, and cost-effective diagnosis of AMI and proper AMI patient treatment obtained from this proposed, multiple cardiac marker sensing device will save many human lives, as well as an enormous amount in health care expenses.